0308托福试题阅读(55minutes)Question1-11Iffoodisallowedtostandforsometime,itputrefies
Whentheputrefiedmaterialisexaminedmicroscopically,itisfoundtobeteemingwithbacteria
Wheredothesebacteriacomefrom,sincetheyarenotseeninfreshfood
Evenuntilthemid-nineteenthcentury,manypeoplebelievedthatsuchmicroorganismsoriginatedbyspontaneous(5)generation,ahypotheticalprocessbywhichlivingorganismsdevelopfromnonlivingmatter
ThemostpowerfulopponentofthetheoryofspontaneousgenerationwastheFrenchchemistandmicrobiologistLouisPasteur(1822-1895)
Pasteurshowedthatstructurespresentinaircloselyresemblethemicroorganismsseeninputrefyingmaterials
Hedid(10)thisbypassingairthroughguncottonfilters,thefibersofwhichstopsolidparticles
Aftertheguncottonwasdissolvedinamixtureofalcoholandether,theparticlesthatithadtrappedfelltothebottom